Process for beneficiation of mixtures of mineral particles

Abstract

An improved process for the beneficiation of mixtures of mineral particles (such as kaolin clays) containing minerals which chelate with hydroxamates. The use of a silicon-containing compound in combination with a hydroxamate results in a more effective separation of minerals which chelate with the hydroxamate.

What is claimed is:  
     
       1. A beneficiation process which comprises the sequential steps of: 
       A. producing an aqueous slurry of a mixture of mineral particles containing minerals which chelate with hydroxamates;  
       B. conditioning the mineral particles by mixing the aqueous slurry with a hydroxamate which chelates with the minerals and which has the formula:                    
        in which R is an alkyl, aryl or alkyaryl group having 4-28 carbon atoms, and M is hydrogen, an alkali metal or an alkaline earth metal, wherein the chelatable minerals are chelated;  
       C. adding a silicon-containing compound to the aqueous slurry; and  
       D. separating the chelated minerals from the aqueous slurry.  
     
     
       2. A beneficiation process as defined by claim  1  wherein the mixture of mineral particles is a kaolin clay. 
     
     
       3. A beneficiation process as defined by claim  1  wherein the mixture of mineral particles is an ore containing titanium, yttrium, cerium, lanthanum, niobium, calcium, tantalum, tin, iron, manganese or copper. 
     
     
       4. A beneficiation process as defined by claim  1  wherein the minerals which chelate with hydroxamates are minerals containing iron or titanium. 
     
     
       5. A beneficiation process as defined by claim  1  wherein the hydroxamate is an alkyl hydroxamate. 
     
     
       6. A beneficiation process as defined by claim  1  wherein R is butyl, hexyl, octyl, dodecyl, lauryl, 2-ethylhexyl, oleyl, eicosyl, phenyl, totyl, naphthyl or hexylphenyl. 
     
     
       7. A beneficiation process as defined by claim  1  wherein M is hydrogen, lithium, sodium, potassium, magnesium, calcium or barium. 
     
     
       8. A beneficiation process as defined by claim  1  wherein the hydroxamate is potassium butyl hydroxamate, potassium octyl hydroxamate, potassium lauryl hydroxamate, potassium 2-ethylhexyl hydroxamate, potassium oleyl hydroxamate, potassium dodecyl hydroxamate, potassium eicosyl hydroxamate, potassium phenyl hydroxamate, potassium naphthyl hydroxamate, potassium hexylphenyl hydroxamate or the corresponding sodium salts of such hydroxamates. 
     
     
       9. A beneficiation process as defined by claim  1  wherein the beneficiated product is a kaolin clay having improved brightness over the starting mixture of mineral particles. 
     
     
       10. A beneficiation process as defined by claim  1  wherein the beneficiated product has improved grade over the starting mixture of mineral particles. 
     
     
       11. A beneficiation process as defined by claim  1  wherein the beneficiated product is a titanium rich kaolin clay. 
     
     
       12. A beneficiation process as defined by claim  1  wherein a fatty acid compound is added during the conditioning step and wherein the fatty acid compound has the formula:                    
       in which R′ is an alkyl, aryl or alkylaryl group having 1-26 carbon atoms, and M is hydrogen, an alkali metal or an alkaline earth metal.  
     
     
       13. A beneficiation process as defined by claim  1  wherein the silicon-containing compound has the formula: 
       
         
           (R″ n —Si—O 4−n ) m    
         
       
       in which R″ is vinyl, hydrogen or an alkyl, aryl or alkylaryl group having 1-26 carbon atoms, n is 0-3 and m is at least 1.  
     
     
       14. A beneficiation process as defined by claim  1  wherein the chelated minerals are separated from the aqueous slurry by selective flocculation. 
     
     
       15. A beneficiation process as defined by claim  1  wherein the chelated minerals are separated from the aqueous slurry by flotation. 
     
     
       16. A beneficiation process as defined by claim  13  wherein the silicon-containing compound is a silicone. 
     
     
       17. A beneficiation process as defined by claim  16  wherein the silicone is a polydimethylsiloxane, polymethylhydrosiloxane, polyethylhydrosiloxane, polymethylalkylsiloxane or a mixture thereof. 
     
     
       18. A beneficiation process as defined by claim  13  wherein the silicon-containing compound is a siloxane. 
     
     
       19. A beneficiation process as defined by claim  18  wherein the siloxane is hexamethyldisiloxane, hexamethyltrisiloxane, disiloxane, vinylheptamethyltrisiloxane, octamethyltrisiloxane, tetramethyldisiloxane, tetravinyldimethyldisiloxane or a mixture thereof. 
     
     
       20. A beneficiated product produced by a beneficiation process which comprises the sequential steps of: 
       A. producing an aqueous slurry of a mixture of mineral particles containing minerals which chelate with hydroxamates;  
       B. conditioning the mineral particles by mixing the aqueous slurry with a hydroxamate which chelates with the minerals and which has the formula:                    
        in which R is an alkyl, aryl or alkyaryl group having 4-28 carbon atoms, and M is hydrogen, an alkali metal or an alkaline earth metal, wherein the chelatable minerals are chelated;  
       C. adding a silicon-containing compound to the aqueous slurry; and  
       D. separating the chelated minerals from the aqueous slurry to produce a beneficiated product.  
     
     
       21. A beneficiated product as defined by claim  20  wherein the mixture of mineral particles is a kaolin clay. 
     
     
       22. A beneficiated product as defined by claim  20  wherein the mixture of mineral particles is an ore containing titanium, yttrium, cerium, lanthanum, niobium, calcium, tantalum, tin, iron, manganese or copper. 
     
     
       23. A beneficiated product as defined by claim  20  wherein the minerals which chelate with hydroxamates are minerals containing titanium or iron. 
     
     
       24. A beneficiated product as defined by claim  20  wherein the hydroxamate is an alkyl hydroxamate. 
     
     
       25. A beneficiated product as defined by claim  20  wherein R is butyl, hexyl, octyl, dodecyl, lauryl, 2-ethylhexyl, oleyl, eicosyl, phenyl, totyl, naphthyl or hexylphenyl. 
     
     
       26. A beneficiated product as defined by claim  20  wherein M is hydrogen, lithium, sodium, potassium, magnesium, calcium or barium. 
     
     
       27. A beneficiated product as defined by claim  20  wherein the hydroxamate is potassium butyl hydroxamate, potassium octyl hydroxamate, potassium lauryl hydroxamate, potassium 2-ethylhexyl hydroxamate, potassium oleyl hydroxamate, potassium dodecyl hydroxamate, potassium eicosyl hydroxamate, potassium phenyl hydroxamate, potassium naphthyl hydroxamate, potassium hexylphenyl hydroxamate or the corresponding sodium salts of such hydroxamates. 
     
     
       28. A beneficiated product as defined by claim  20  wherein the product is a kaolin clay having a brightness value which is improved over the brightness value of the starting mixture of mineral particles. 
     
     
       29. A beneficiated product as defined by claim  20  wherein the product has improved grade over the starting mixture of mineral particles. 
     
     
       30. A beneficiated product as defined by claim  20  wherein the product is a titanium rich kaolin clay. 
     
     
       31. A beneficiated product as defined by claim  20  wherein a fatty acid compound is added during the conditioning step and wherein the fatty acid compound has the formula:                    
       in which R′ is an alkyl, aryl or alkylaryl group having 1-26 carbon atoms, and M is hydrogen, an alkali metal or an alkaline earth metal.  
     
     
       32. A beneficiated product as defined by claim  20  wherein the silicon-containing compound has the formula: 
       
         
           (R″ n —Si—O 4−n ) m    
         
       
       in which R″ is vinyl, hydrogen or an alkyl, aryl or alkylaryl group having 1-26 carbon atoms, n is 0-3 and m is at least 1.  
     
     
       33. A beneficiated product as defined by claim  20  wherein the chelated minerals are separated from the aqueous slurry by selective flocculation. 
     
     
       34. A beneficiated product as defined by claim  20  wherein the chelated minerals are separated from the aqueous slurry by flotation. 
     
     
       35. A beneficiated product as defined by claim  20  wherein the silicon-containing compound is a silicone. 
     
     
       36. A beneficiated product as defined by claim  35  wherein the silicone is a polydimethylsiloxane, polymethylhydrosiloxane, polyethylhydrosiloxane, polymethylalkylsiloxane or mixture thereof. 
     
     
       37. A beneficiated product as defined by claim  20  wherein the silicon-containing compound is a siloxane. 
     
     
       38. A beneficiated product as defined by claim  37  wherein the siloxane is hexamethyldisiloxane, hexamethyltrisiloxane, disiloxane, vinylheptamethyltrisiloxane, octamethyltrisiloxane, tetramethyldisiloxane, tetravinyldimethyldisiloxane or a mixture thereof.